Open-Phase Fault-Tolerant Predictive Control Strategy for Open-End-Winding Permanent Magnet Synchronous Machines Without Postfault Controller Reconfiguration

Abstract

Fault-tolerant control is normally required to achieve continuous operation under postfault modes in some critical fields. Regarding the remedial strategy for open-end-winding permanent magnet synchronous machines (OW-PMSMs) in the case of open-phase fault, the typical way is to reconfigure the controller after the fault is detected. Different from those mainstream control strategies, which account for the postfault situations by reconfiguring controllers or modulators, the fault-tolerant predictive control strategy proposed in this article handles the asymmetry produced by open-phase fault in a different manner. By combining the predictive control strategy with an embedded vector-resonant control scheme, the proposed strategy can achieve effective regulation of OW-PMSMs in both pre- and postfault operations. Controller reconfiguration and switching between pre- and postfault control modes based on fault detections are thus avoided. Besides, with the rotor flux harmonics taken into account and benefiting from the proposed zero-sequence controller, the triple-frequency component in the zero-sequence current is successfully suppressed to reduce torque ripples while the fundamental-frequency component in the zero-sequence current is properly retained under postfault operations, which is required in order to obtain an uninterrupted rotating magnetic field after one phase is open circuited. Experimental validations are conducted to verify the effectiveness of the proposed strategy and its superiority over conventional voltage compensation methods.